The present invention relates to office furniture and filing systems of a structurally strong and reinforced nature while simultaneously maintaining an attractive and aesthetically pleasing appearance, in particular, a relatively `petite` appearance that belies the true structural integrity of the furniture piece.
The structural arrangement of the present invention further facilitates a `family` of furniture pieces in which structural elements or modules may be combined in differing configurations to create tables, filing systems, desks, computer and typewriter stands, shelves and other furniture pieces of correspondingly differing sizes and capacities. The present system, for example, permits fabrication of single, dual and triple level furniture pieces simply by the selection of appropriate joint connectors and the progressive assembly of additional levels thereon--much like the addition of another floor in the construction of a new building. Both fixed-position systems as well as `rolling` systems, i.e. systems with castors fitted to the legs for movement within the office environment, are herein contemplated.
A variety of prior art systems have been proposed, some including tubular and multi-axis joint connectors while others have utilized diagonal braces, gusset plates and similar well-known mechanisms to achieve varying degrees of structural rigidity. None, however, combine the petite appearance and modularity of the present invention with the requisite structural integrity.
The need for a strong, rigid design cannot be overemphasized when it is remembered that office furniture may be heavily loaded (e.g. typewriters, computers, piles of files etc) and often subjected to substantial side-loads imposed while pushing the furniture over rough floors, carpets, molding strips and door sill jams.
It has been found that ordinary tube/joint systems do not have sufficient strength to resist the side-loads (e.g. bending moments) placed on the connector joints under many of the above-described conditions. It is easy to appreciate how such overloading can occur in view of the fact that furniture pieces may extend more than forty inches above the floor; that usually only one leg encounters a `resistive` barrier to movement at any given moment; and that the more weight placed on the furniture piece, the more resistance to motion the obstruction will offer and, correspondingly, the more lateral force that will be required to overcome such blockage.
And to compound this already ill-conceived scenario, the momentum of a moving piece of furniture--should the piece suddenly stop (e.g. upon the unexpected encounter with an `immovable` obstacle)--translates into, and imparts, a hugh angular moment to the affected leg joint that may exceed several thousand inch-pounds. Although tubular/joint construction has many advantages, including modularity, easy of fabrication, automatic spacing of shelves, racks and member, it simply cannot handle the large angular moments in the ordinary work-place environment.
While angular bracing and gusset plates represent well-known strength-enhancing solutions, neither is deemed to be aesthetically satisfactory and, further, both increase the complexity and time required to assemble furniture pieces. (As with `Christmas toys`, the lay consumer is generally saddled with assembly responsibility). The present invention, therefore, seeks to combine the modularity of tubular construction with a reinforcement system that is strong, easy to assemble, and that mates and comports well, in a design-sense, with a tubular superstructure.
As described in more detail hereinafter, the present invention utilizes special channels, arranged adjacent and parallel to the tubular members, to enhance furniture rigidity and strength. It should be noted that these channels are not utilized, as might first be suspicioned, as ordinary load-bearing beams, nor are they bolted, welded or otherwise rigidly interconnected to define a self-sustaining rigid box structure. Rather, the height of the channel (with its upper and lower lip surfaces) acts, in concert with the tubular members, to define a `parallelogram` (in this case, a rectangle) that serves to relieve and redistribute stress otherwise acting directly on the joint connectors and to absolutely preclude the angular rotation of any leg with respect to the other legs and to the overall furniture structure.
To this end, and to minimize assembly complexity and time, the present invention employs a system of channel self-positioning and self-locking. No alignment or positioning is required. Nor are any special or additional channel attachment mechanisms required.
More specifically, two channels are provided and required adjacent each tubular joint connector. These channels are dimensioned, in the first instance, so that the upper and lower channel lips or surfaces may overlap thereby providing an interference-free mating therebetween. A pair of holes are provided in each channel end, as described more fully herein, to capture the tubular leg members and to effect the above-noted channel positioning and locking.
A first hole, having a diameter substantially equal to, but slightly larger than, the outer diameter of the leg member, is placed in the lower channel lip. This hole permits the sliding engagement of the leg therethrough while being of such close dimensional tolerance that the leg may not move freely laterally within the hole. The second hole, placed in the upper channel lip, is dimension substantially equal to, but slightly larger than, the inner diameter of the leg member, but in no event may it be of diameter greater than the outer leg diameter. Thus, the leg member, while freely moving through the lower lip hole, is blocked from insertion or movement through the upper lip hole. This is key to the automatic alignment and retention of the channels.
The various lateral and vertical (leg) tubular members are relatively rigidly interconnected by joint connectors. Joint connectors are characterized by plural, and generally orthogonally-oriented extensions that are forced into tube ends thereby rigidly retaining the several tubular members in fixed, orthogonal relationship to one-another. (Although `rigidly` interconnected, it must again be stressed that the tubes and joint connectors are susceptible to deformation and failure under the bending moments placed thereon during normal use.) The joint extensions are dimensioned, in cross-section, substantially equal to, but slightly larger than, the inner diameter of the tube members thereby facilitating the above-noted rigid engagement between the joints and tubes.
In view of the above discussion relating to the engagement between the joint connectors and tubes, it will be understood that the upper channel holes, while too small to admit passage of the tubular legs, does allow passage of the joint extensions. Thus, the channel is positioned and retained by the expedient of sliding the leg member upwardly through the lower channel hole until the leg contacts the upper channel lip, thereafter, forcing the joint extension downwardly through the upper lip into the tubular leg member.
When fully engaged, the channel upper lip is tightly `sandwiched` between the leg member and joint (in a fixed, predetermined position) and consequently prohibited from sliding either upwardly or downwardly along the leg. In fact, two channels--the adjacent channels that define the corresponding sides of each corner--are simultaneously positioned and captured under each joint connector and, again, in a manner not necessitating channel alignment nor additional channel mounting or retention hardware. It will be appreciated that the upper and lower holes may be reversed with the lower channel lip being captured and rigidly held between the lower end of the tubular member and the joint connector, now positioned below the channel.
As noted, the strength of the above-described combination structure is not achieved through the intrinsic load-bearing capability of the channel members alone, rather, by reason of the height of the channels and the corresponding spacing, in particular, of the lower channel lip below the joint connector. The existence of the lower channel lip precludes the rotational movement of the tubular leg about the joint essentially converting any angular moment to a relatively non-destructive linear force.
The upper channel lip serves two strength-increasing functions. First, it, too, functions to inhibit rotational leg movement. Second, it acts as a direct linear brace against the inadvertent, forced release of the joint extensions from the lateral tubular members. In this manner--short of literally destroying the channel members--the structural integrity of the furniture piece is virtually assured.
The above-described combination provides important aesthetic as well as structural benefits. As noted, there are known prior art bracing arrangements that solve the strength problem. But strength, alone, does not make an acceptable furniture product particularly when considerations of office decor must be weighed. While the overall aesthetics may not be fully appreciated from the figures herein, it is significant that the structural combination of adjacent tubes and channels removes the appearance of `sterility` and `blandness` that is believed to otherwise manifest with either tubes or channels, alone.
It is therefore an object of the present invention to create a family of stands, racks, and furniture, particularly suited for use in an office environment. It is another object that the furniture be modular, that is, defined by a limited number of component types which are combinable to produce differing, larger or multi-level furniture pieces. A further object is a furniture line that is suitably rugged and aesthetically acceptable. A further object is a furniture line that requires no special assembly talent; that is not complex in structure or assembly; and that may be assembled quickly. A further object is to provide dual functional members that serve both aesthetic and reinforcing functions.